Thousands of people protested in the streets of Caracas on Saturday against a second attempt by President Hugo Chavez to change the constitution to let him govern Venezuela as long as he wins elections.
Opinion polls give him a slight lead before a referendum on 15 February on whether to allow the president and other politicians to run for re-election as many times as they like.
Voters rejected a similar proposal in 2007.
Mr Chavez has nationalized industries and raised spending on health and welfare since he took office in 1999 but says he needs more time to build what he calls "21st Century socialism."
